Throttle dash pot



April 10, 1956 A. M. BABlTcH 2,741,474

THROTTLE DASH POT 2 Sheets-Sheet l Filed oct. 14, 1950 April 10, 1956 A. M. BABITCH THROTTLE DASH POT 2 Sheets-Sheet 2 Filed OC'. 14, 1950 3 n v en tor @Z/WW @falsa Je? f Gttornegs United States Patent C i Tmzorrtn oasis rot Abraham M. Babitch, deceased, late of Flint, Mich., by Sadie Babitch, executrix, Detroit, Mich., assiwor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application Qctcber 14, 195i), Serial No. 196,133

11 Claims. (Cl. 267-1) This invention relates to diiierential pressure chamber or pneumatic devices for resisting or slowing down the rate of movement of other devices in one or more directions. The device is particularly applicable for use as an antstall device for preventing the stalling of automobile or other internal combustion engines when the throttle controlling the engine is suddenly released.

An object ot' the invention is to provide a simple and reliable antstall device for automobile engines.

Another object of the invention is to provide an antistall device which will consist of a relatively lsmall number of parts which do not require excessive and expensive tooling in the manufacture and assembly thereof and which can be easily installed on an automobile engine either as original equipment or as an accessory to engines already in use.

In the accompanying drawings:

Figure 1 is a fragmentary view of an automobile engine carburetor having an antstall device embracing the principle of the invention associated with and operated by the throttle valve of the carburetor.

Figure 2 is a longitudinal sectional view through the antstall device illustrated by Figure l. Figure 2 is taken substantially in the plane of line 2-2 on Figure 1 looking in the direction ofthe arrows thereon.

Figure 3 is a fragmentary view illustrating a portion of the diaphragm and valve structure embraced in the antistall device illustrated by Figures l and 2. Figure 3 is taken in the plane of line 3 3 on Figure 2 looking in the direction of the arrows thereon.

Figure 4 is a fragmentary view of the antstall device shown by Figure 2 but with the parts thereof illustrated in a different operative position.

Figure 5 is a perspective view of a metering member or disc embraced in the antstall device illustrated by the preceding figures.

Figure 6 is a longitudinal sectional view illustrating a somewhat diierent form of antstall device embracing the principles of the invention.

Figure 7 is an exploded perspective view showing how the various parts of the antstall device illustrated by Figure 6 are assembled on the operating shaft of the device.

Referring to Figure l, there is illustrated at 10 a part of a downdraft charburetor which is adapted to be employed on an automobile or other engine.

The carburetor 10 is provided with a throttle valve having an operating shaft 11 projecting through a coupling 12 by which the carburetor 1t) is connected to the inlet manifold for the engine with which the carburetor 10 is employed. The shaft 11 has a attened end to which is attached an operating lever 13 by which the throttle is operated by a rod 14. One end of the rod 14 is pivotally connected to the lever 13 as is indicated at 16 while the opposite end thereof may be connected through various levers and links to an accelerator pedal or other suitable device for operating the throttle lever 13 from any remote location. Y

The throttle for the carburetor 10 has a suitable idling Patented Apr. 10, 195.6

position in which the throttle is partly open at all times for the purpose of admitting to the engine enough of a charge to maintain the engine in operation at low speed and generally at no load. Such idling position of the throttle for the carburetor 10 is determined by a screw 17 which is adjustably secured in a threaded opening formed in a part 18 of the lever 13. The end of the screw 17 beyond the part 18 is adapted to engage any suitable stop projecting from the casing of the carburetor 10. A suitable spring not shown but generally associated with the rod 14 is adapted resiliently to urge the lever 13 into a position in which the end of the screw 17 will engage the stop referred to.

It will be apparent from the structure disclosed that the throttle valve will be opened when the lever 13 is rotated in a counterclockwise direction by pulling upon the rod 14 and will tend to be closed to idling position when the lever 13 is rotated in an opposite direction by an opposite movement of the rod 14 and into a position in which the screw 17 engages the idling -stop referred to.

The lever 13 also is provided with a laterally projecting arm indicated at 19 and the arm 19 is adapted to engage and to operate the actuating shaft 21 of an antstall device indicated generally at 22. The antstall device 22 is provided with a casing 23 through which the shaft 21 projects and which comprises casing sections indicated at 24 and 26. The casing section 26 has an annular end wall indicated at 27 and to the exterior surface of which is welded or otherwise secured a bracket 28. The bracket 28 has an opening through which the shaft 21 projects and has suitable laterally bent parts 29 projecting toward the carburetor 10 and by which parts 29 the antstall device 22 is secured rigidly to the carburetor 10 and in operative relation to the arm 19.

The position in which the antstall device 22 is secured by the bracket 28 with respect to the carburetor 10 is a position in which the axis of the shaft 21 is approximately at a right angle to a radius between the contact point on the arm 19 and the center of the shaft 11 when the throttle-operating lever 13 is in engine idling position.

- The casing section 24 comprises an outwardly depressed end part 31, an annular end wall 32 and an inwardly and angularly disposed annular peripheral wall indicated at 33. Peripheral wall 33 terminates in an outwardly disposed flange indicated at 34.

The casing section 26 comprises the outwardly depressed annular wall 27 and inwardly depressed annular wall 36, a sloping peripheral annular wall 37 and an outwardly disposed radial iiange 38 which is disposed in directly opposed relation to the ange 34 projecting from the wall 33.

A ilexible diaphragm 39 is securedbetween the anges 34 and 38 by crimping the outwardly projecting edge of the flange 38 around the ange 34. The crimped edge of the ange 38 is indicated by the numeral 41.

The central part of the diaphragm 39V is reinforced and the movement thereof is limited by a pair of oppositely disposed plates indicated at 42 and 43, each of which is provided with a anged edge indicated respectively at 44 and 46 and each of which flanged edges is annular in formation and projects in a direction away from the diaphragm 39. The flange 46 is diposed in opposed relation to the annular end wall 36 for limiting the movement of the diaphragm 39 in one direction (Fig. 2) while ange 44 is disposed in opposed relation to an outer peripheral part of the end wall 32 for limiting the movement of the diaphragm 39 in the opposite direction (Fig. 4).

, A spring ,47 having one end disposed within the depressed end 31 of the casing section 24'and the opposite end abutting the central part of the plate 42, tends resiliently to urge the diaphragminlto what might be said to be the expanded positionA (Fig. 2) of the diaphragmand n mentfof the diaphragml Y casing structure. In the extreme expanded position ofV the diaphragm 39 the flange 46'of`the plate 43 rests upon and abuis the annular end wall 36 of the casing section 26. The .diaphragm 39=is moved-.towardand'awaygfromthe expanded@osition.referreclttov and. against theffcrcenf the spring 41, by the ei'gerating` shaft 21@ which engages. projects through thefcentralr portion onthe.diaphragm35il Y and. the. central portionsgf o,- the plateslAZ. and 43. Y

Y of the shaft 21 which is adapted to abut-theradjacentsnrface-.otV a,- disc-.shaped metering member 52Y which also isrnrOy-idedawithsa squareopeningdisposed-centrallyrthereof-4 and; indicated-by one-ofi thenunttel'alsi 48.

Thegmeteringfmember 52 istdisposedfbetweentheshoul:

der. 517; and the adjacent surface of thematic-43. AThe two plates 42.; and 43` are; rigidly secured; together upon the diaphragm 391and;against-thefmetering member 52 abutting thefshonlderl51- by upsetmetallic portions or staking 53-whichis formed, at intervals-around, the pe.-

ripheryy of; the. extremity of thereduced end 49l of the saar; er.,

The openings, 48m the members-.52, 43,39, and.42-a,re ot snchsize as to .-slidably-tit:the reduced; end49. of. the shaft 21-V with, the linear sides-'ofv thegopenings 48 .being guinea.

movement of fluid in one direction between the compart-V ments 56 and 59 there is formed in the plates 42 "andllV taugen-tto the.; cylindrical.. surface of the` reduced'. end145! n andzengaging thezcylindrical surfacemidwaybetweenthe ends of' thesidesz Snch construction,,provides/four corner spaces. .54; which extend: through:- all A. oi; thermembers z52, 433 39,- andA 42;.andywhich1onvthm sidef of; the. diaphragm 39:adjacentl the;v casing Vsection 24v communicate .withifa' uidY compartment 56 which is providedtby theI diaphragm 39fand-:theacasing section 24;

The opposite lends, ofthezcornerrspacest ,communicate with an annular; reeessrfii'l" which-isiormed in the; shaft 21s inside they annular shoulder 51.,

In: order: to; provide means, forf: meteringther ow of liuid'to and from the compartmentirwhieh may.` be. causedfby movemento; thediaphragm,V bythe-shaft 2,1,v thereis formedgatonefof .the corners ot the opening 48;.ingmetering memberI 5.2. `azradial slo t;(Fig; 2 f which .is indicated by-'the :numeral 5.8:. 'Ihre` slot 58 atpitszinner end communicates with the annular; recessf 57. andithey outer end thereof communicatesxwithr. a; eompartmenti59 termedv between-,the-,diaphragm .3 9- and; the. casing vsection 26j.,- In se communicatinggwitlr thercompailment;l 59.. the, end-of the slot;58r:projects. beyond thegrperiplieral .fedgeaof the shoulderu portion 51 ofi .theshaft 2.1..

and the diaphragm39 a one-.way valve which is indicated generally by the numeral 61 (Fig. 3).

The Valve 61 is formed by providing an opening 62 in the plate 43 which isl at allltimesin open communication with the compartment 59. In the closed position of the valve 61 the opening 52 is adapted to be covered by a ap 63 whichis formed-inthe diaphragrn.39 byY apair.v of oppositelydisposed arcuate slots indicatedrat 64. The slots 6d arerfermed in the diaphragm;39.on-oppositefsides of the opening 62, and the ilap 63 is heldin; positionV between the slots by connecting parts of the diaphragm whichV extend between the slot ends.

The slots 64 communicatev/ithandlare disposed within the iimits of an annular depression 66 (Fig. 2) which is formed within the surface of the plate 42 onV the side thereof adjacent the -diaphragm39. Openings V675- (Eig, .3)

termed inthe plate 42 around thecentral portion ofi.

Y the-depression66 for the-purpose of proyidingfopen'come munieation between the depression 66-and1the expandable andcontractable compartment 56. f

While assembling the; device,V itis-.apparentz that -itwilli be necessary to .position the plate'43 so thatthe'opening. 62. therein Ywill be-in thecentral part ofthe flap-631m .the diaphragm 39. lt is not necessary to locate. theplatei42, in any predeterminedposition.with respect to thefslots and the opening 62..

Thewall'l othecasingseetion 26 isilangedout-` wardly. at thev central portion thereof as is,V indicated; att and theopening within the` frange may begof hexagonal shape/for the. purpose of litting and slidablyreceiv-ingfthe. similarly formed hexagonal surface of ,the.shaft;21.

In the structure disclosedby Fignrejs'l to;5;4the. shaft Zisl madeof suchhexagon'al external surface configuration Y for Ithe ,purpose of ,preventing rotation: ofthe'shaft and Ythe*consequent rotation .of any of the, .assembledparte throttle or idling position volithe: enginefwitlnwhiehthe deviceissemployed.- lnsuch position theshaft 2Lm'ay be described asi beingjn aretracteri positionizin which diaphragm 39 and the plates and otherpartsgassociated It will be apparent that movement of the diaphragm139 I eration that may-beemployed imformnggtheiopening 485m themembergz... Y

If-lfnrtheri will :be: apparent ,.thatrthfefgradial slot;58;: ,the annular channel 57- andethefcorners 54.*atfallv times-provide -a uniform' and; contnuousaopening. betweenl theeeom-i partments S6 and\.59.and that theV metering; of :the'iiow `of fluid between-v the twov compartments ineitherdirection will ia't all times-provide a--uniformfr'e'rsistance totheamov@ ln'orde'r-'toA-provide means' forincreasing'rthetrateof therewith; will beimoved inwardly. in 1 sach Vmannen-:asl to reduceftoaminimum theisizer of the fcompartmentfit. such position the flange 44 of thesplate: 42; may-'engage andi rest-upon the annularendisnrface: 32 ofthe-.sensing section 2.4i.'4 Also asv/ill beapparent 'fromzFigureAy the spi'ing47will befcompressed .until thetconvolutions; there4 ofzlierclosely adjacent one another.

When-fthefthrottlefis opened .or moved :awayffrom'fthe idling position of ,the;throttler by pulling upon the rod 14' androtatingftheilever 13 ina counterclockw'iseidirection, itcwill {bet-apparent that-the vspring .47 will cause. Athershatt 21e-tof fellow-thegarm luntil thefdiaphragrnlisin its expanded position.; In the extreme expandedcpositionlof thefdiaphragm 39 the Vflange 46;of:the.pla.te;45 will'rest upon thesannular endwvall 36 of the/casing;sectionr-A vAs will tbe; apparent from observing" the sizev and: relation: of the partsshown inPgtu'esl to .5, theiiangedlwillrest uponfthe'endrwall within a relativelyaew'-degreesfo rotation ofthe throttleflever 15' away from: theiidlingfpjo'si-- tion-of theathrottle: Thereafterduringtherdrtlierfopening movement of thethrottle, the arm 19 will rotate-away from the 'head-` 71 of 'the screw '69Ty andthier throttle will arenaria thereafter continue to operate throughout the normal range of operation without in any way affecting the antistall device 22.

In the structure shown by Figure 4, the valve structure 61 is shown in the position in which the parts thereof will be located at the beginning of the previously described movement of the throttle from idling position to open position. At the beginning of such movement it will be apparent that the initial movement of the diaphragm 39 away from the casing section 24 will cause a slight reduction in pressure in the compartment 56 and this reduction in pressure will cause the ap 63 of the valve 61 to move away from the opening 62 in the plate 43 and into engagement with the adjacent surface of the plate 42 and within the depression 66. Such movement of the flap 63 will permit air to ow from the compartment 59 through the opening 62, through the space between the ap 63 and the plate 43, through the slots 64, into the depression 66 in the plate 42 and surrounding the ap 63 and thence into the chamber 56 through the openings 67. Since these openings form a large and relatively unrestricted passage, it will be apparent that the spring 47 will quickly move the diaphragm into its opposite position in which the iiange 46 will be seated upon the end wall 36. The diaphragm 39 therefore will move into the expanded position of the device practically as fast as the throttle lever 13 can be moved away from the idling position of the throttle.

During such opening movement the duct or air passage formed by the slot 5S, the channel 57 and the corners 54 also will be open and will aid in the transfer of uid from the compartment 59 into the compartment 56 to permit the expansion of the bellows 39 into the expanded position referred to.

lf the throttle of the engine is suddenly released, then the throttle lever 13 will be rapidly rotated in a clockwise direction and ,will engage the head 71 of the screw 69 of the actuating shaft 21 of the antistall device 22 with the parts thereof in the position in which such parts are illustrated in Figure 2. Such position of engagement will be several degrees of rotation of the throttle lever 13 prior to the position in which the throttle stop is engaged by the screw 17 and when the throttle is rotated into engine idling position.

As soon as the lever 13 has rotated far enough so that the arm 19 engages the screw head 71 the shaft 21 will tend to move the diaphragm 39 against the compression of the spring 47. It will be apparent that the initial part of such movement will tend instantly to increase the iluid pressure within the compartment 56 and thereupon suchV increase in uid pressure will immediately move the ap 63 against the adjacent surface of the plate 43 and in such position as to completely close the opening 62.

The valve 61 therefore will not participate in the transfer of uid from the compartment 56 to the compartment 59.

The only passage available for such transfer of uid is the passage provided by the corners 54, the annular channel 57 and the metering slot 58.

In view of the fact that the cross-sectional area of the slot 58 is the limiting factor in the transfer of iuid through such passage and that the difference between the cross-sectional area of the slot 58 and the area of the opening 62 lwhich is exposed by the opening of the valve 61 is great,

rit will be apparent that the diaphragm 39 will tend to fmov'e into a position in which the ange 44 will engage the to the final closing movement of the engine throttle will prevent a violent change in the rate at which the charge to the engine is supplied by the carburetor 10, and hence will prevent the 'engine from stalling when the 'throttle is moved into engine idling position.

The structure shown by Figures 6 and 7 of the drawings is similar to that shown by Figures l to 5 except for the fact that the parts forming the valve and metering passage features of the structure are formed in a somewhat different manner. In Figures 6 and 7, the shaft 121 for operating the antistall device 122 is a cylindrical shaft. In some instances it is considered preferable to employ such a cylindrical shaft to make it difficult or impossible for a wrench to be used on the shaft. It sometimes occurs that wrenches are applied to shafts of this kind and under such circumstances it is possible that suflicient pressure may be applied to the shaft to twist the antistall device entirely out of its adjusted and operative position.

The operating end of the shaft 121 also is formed in a slightly dierent manner by employing a press iitting studs 169 having a cylindrical head 171 in an axial opening formed in the end of the shaft. The stud 169 may be forced in the opening to any desired extent for the purpose of properly adjusting the positionv of the shaft 121 relative to the throttle lever 13 of a carburetor such as that illustrated at 10 in Figure l and with which the device illustrated in Figures 6 and 7 may be employed.

The shaft 121 is adapted slidably to project through an axial opening formed in a sleeve 160, the reduced end of which may be welded or otherwise secured in an axial opening formed in a casing section 126 of the antistall device 122. A nut 101 engaging the threaded exterior surface of sleeve may beemployed for the purpose of fastening the device to a carburetor by the use of a bracket such as that illustrated at 28 in Figure l.

The casing 123 of the antistall device 122 also cornprises a second and oppositely disposed casing section 124, the two being secured together upon a'diaphragm indicated at 139 by anges 134and 138, the latter being crimped or bent around the formeras is indicated at 141. The casing sections 124..,and 126 are otherwise similar to the casing sections 24-arid 26 illustrated in Figures l to 6, and hence will not be Afurther described.

The diaphragm 139 is secured between a pair of plates indicated at 142 and 143 which in turn are disposed between a valve cage indicated at 102 and a metering member or device indicated at 152. yThe plates 142 andl 143, the diaphragm 139 and the metering member 152 all have openings 148 therein and each of which is formed in the shape of a square, these openings being adapted totangently lit the cylindrical exterior surface of a reduced end 149 formed on the shaft 121 adjacent a cylindrical shoulder 151, also formed as afpart of the shaft 121. Between interior surfaces of the openings 148 and the exterior surface of the reduced end 14.9 are corners 154 which provide a continuous duct or passage through the diaphragm 139, the end plates 142 and 143 and the metering member 152. The ends of all of the corners 154 adjacent the shoulder 151 also communicate with an annular channel 157 also formed within the shaft 121 and within the annular shoulder 151.

The metering member 152 is provided with an angular slot indicated at 158 which projects across the annular shoulder 151 and provides communication between the channel 157 and the compartment 159 which is formed by the diaphragm 139 and the casing section 126. The opening 14S which is provided in the plate 142 has a plurality of laterally bent flanges indicated by the numerals 193, there being one of these anges projecting from each side of the opening 143. The flanges 1%3 project away from the diaphragm139 and toward the valve cage 102 and into an annular recess 104 which is formed around a cylindrical opening 166 on which the cage 102 is mounted upon the cylindrical endl-49 of the -shaft 121. The spacers or ilanges 103 provide suicient space between the plates 142 and the cage 162 for an angular valve disc indicated at 107 to be positioned between. the twoiand to:Y Ybev movable into. and'. out of" valve-closing position. p

The. valve cage 102, the platesl 142 Aand'- M35- the diaphragmA 139-, and" thefmetering` member 152i are'allwhich collectivelyprovide: a'- valve-passage or orifice 169 adapted to be controlled by the valve disc 107. The openings- 109'also mayI bel employed in assembling the devieeinasmuch as a rod can be projected through all of these openings for-the purposeof'properlyaligning the parts beforethey' are assembled' on the` shaftf'end 1495and againstthe vshoulder 1'51. Y

vIti'willbe apparentithatzwhenthe disc'107 is forced against the-.platee1'42 byfanlincrease in pressure in compartment 156', the disc 10T will close the opening'109. The closing of the=opening 199l will tend to provide increased resistanceV to the movementof; the diaphragm 139'in such manner as to 'reduce theicapacity of the compartrnentV 156.

Itwill'be apparent, however, that the diaphragm 139 can be so moved to'reduce'the capacity offthe compartment 156. by the provisiony ol" the metering passage formed by'the'- corners I54of'' the openings-148, the channe1157'and the radia1slot'158 which-extends across the` shoulder 151.

The 'space providedbythe corners 154 will communicate with the compartment1156 throughv the spaceswhich areprovided at theopposite endsof'the flangesV 103'and the'space'providedbetweenthe"valve cage 102 and the disc 107Y when the disc 'is initsJvalve-ciosing'- position.

In order to` provide initial freedom for the tiow: of fluidbetweenthe valve cage 102 and the discv 107 when the'disc 107 is inits'vallve-closing position and to admit air to the adjacent Vsurfaceeofl the disc 1'07 for'closing the valve; thereris providedaiplirra'lity of'radially disposed notches indicated at 111" and f Whichare frormedinwardly of the periphery ofv the cage--102 and extendl to within a-short distance of' the spaces provided betweenthe opposite ends-ofv the flanges 103. Under such c-ircum-V stances the'airv from the compartment 156`willflow`v into the'v metering passage previously des'cribed'through the radial slots 111'. e i

A spring 1`47"Whichl is'A disposedbetween 'the' central partl of thev casing '-"seetion 124i and the' valvev cage'102 will'tendlto urgethediaphragmstructurein-to'itseexpanded positinand'infwhieli; position the adjustable head`171 towardengine'idling position.

Th'e-structurediselosedbyFigures- 6 andTis otherwise Y theV same and will" operateV the same as theY structure disclosed' by Figuresl 1` to Sand the-description of opera'- tion of the structure disclosedby'Figuresl'to 5 likewise will apply to the stmcture disclosed byl Figures 6 and 7.

I' claim: Y

l. A fluid aetuatedresis'tancedt'evice comprising-acasing, aexible diaphragm extending across` said'casing' `and Vforming'- in one end 'offsaidlcasing 'achamber; of V"variable size, a shaft secured tothe-central part 4of 'saidj diaphragm for movingl saiddiaphragmlfor vlarying the'size'ofsaid chamber, anv opening frm'ediin said "diaphragmeadjaeent saidfshaft for transferringu-idto and from said lchamber, an annular rece-ss on ,saidshaft 'communicati'ng'` with saidlopeningland'a member disposed between ysaid'diacommunication withA saidV open-ingfand'the other in open .communicationzwith Ysaid casing-Con one side oisad diaphragm .2. `A.pneumatic.resistance device-comprising a casing, aexible diaphragm projecting. across saidY casing-andforming on one side ofsaid diaphragm and within. said casingza closed chamber of variablesize,fmeans projecting through an openingformed in :said-diaphragm forV movingv saiddiaphragmior varying theV size of'said chambensaid opening insaid diaphragm being larger thansaid means to'. provide a ducttthrough said diaphragm for transferring iiuidito. and from said chamber, abutment? means on `said first mentionedmeans and a metering member disposed between said diaphragm and said abutment meansand having a radial slot formed therein,V one end of said. radial. slot being'v disposed in open communication with saidduct and leading outwardlyk therefrom and providing 1 comnulnicationbetween said duct and'theinterior of. said casing on' one side of. saiddiaphragmior metering. said fluid transferred to and from said chamber.

.3. A pneumatic resistancev device comprising a casing; a'il'exible diaphragm extending across said casing,lanshat projecting' througnthe .central part of said diaphragm for moving said diaphragm within said casing, annular shoulder 'means' formed outwardly of saidy shaftononc side of. said diaphragm. for moving said diaphragm .by

said shaft; a metering member. disposed. between said shoulder meansand said-diaphragm and comprising a sl'ot extending across. said. shoulder, a duct formed in. said diaphragm and communicating at one end withisaidslot and at the opposite end with .the side ofzsaidrdiaphragm opposite saidv metering? member, .and said: shoulder `having a passage formed. therein. communicating with saidv duct andfslot. Y

4.- A pneumaticresistance device comprising: acasing; a diaphragm secured=to saidlcasing and'projectmgacross said casing,V a pair of plates engaging opposite. central portions of saiddiaphragm, an annulardepressioni formed inthe' surface of oneof said platesadj'acentsaid da# phragm ytoi-'permit the movement' ofV said diaphragm'- to`- ward and away from-'each of= said plates;v lfluid passage meansin saidone of said plates between said depression and the interior` of said casing, an 'opening` formedin the other of saidiplates in'oppos'ed relation to sa'iddeQ pression,V and aslot formed in'said diaphragm in'opposed relation fto said' depression butin radially spaced relation to said opening.

5". A pneumatic resistancedevicecomprisingapair of casingsections 'having converging' angularly disposed annular peripheral parts terminating in parallel il'anges; a flexible diaphragmextendingfacross-the casing formedby .saidA sections'and secured between said yiian'ges,l Vone-of said flanges having extended edge portions-'crimpedfab'out the; other of said' tianges, a pairoparallel end walls formed in saidsections in inwardly/'disposed relation rto' said annularp'eriphera'lportions, means forrmovingisaid diaphragm including a pair of platesengaging the' central portion ofsaiddiaphragm and disposedon oppositeFsides of said diaphragm, valve means associated with said pla-tesrand said `diaphragm for transferring'Y uidi in'i said casingbetweenithe oppositev sidesof said diaphragmat a rate dependent upon the-direction -oflmovem'ent of. said diaphragm, andisaidplates being provided .with `oppositely disposed peripheral flanges formed. at'the'edgesthereof and inopposedrelation to .said `end ywallsV of said casing forlimiting the'movement ofsaid diaphragm in opposite directionswithin said casing. Y g

6.. A pneumatic resistance device comprising a casing havinga flexible diaphragm secured therein and extendingrthereacross, a pair of plates engagingthe central 'portion of said diaphragm on opposite 'sides'vth'ereo a'depression forrnedinone of' said plates and providing'a space'fertileV movement of said diaphragm'beowfeensad pla-tes; afpurality of'openings formed in'said one' plate( in communication with saiddepression, a` pluraiity/ of openings 1 formed insaid diaphragm' in opposed relation to said "f depression buti in` lateraily spacedJ relation 'to an VVopeninginthe other of vsaid plates "afsprinfg inf said "casing between said casing and said one of said plates for resiliently urging said diaphragm in one direction, shaft means projecting within said casing and attached to the said plates for moving said diaphragm against the force of said spring, and metering means deiining a passage between the compartments in said casing formed by said diaphragm.

7. A pneumatic resistance device comprising a casing having a diaphragm secured therein and projecting thereacross, a pair of oppositely disposed plates engaging oppositely disposed surfaces adjacent the central portion of said diaphragm, a fluid metering disc engaging one of said plates and having a radial slot formed therein and with the opposite ends of said slot communicating with the interior of said casing on the opposite sides of said diaphragm, a plurality of registering openings formed in said diaphragm, said plates and said disc for transferring fluid within said casing between the opposite sides of said diaphragm, a valve associated with one of said plates for preventing the flow of fluid in one direction through said openings, valve cage means for securing said valve in position relative to said openings, a central opening in said diaphragm, and a shaft projecting through said plates, said diaphragm opening, said discs, and said valve cage means for operating said diaphragm and for securing said plates, diaphragm, discs, and valve cage means together for operation as a single unit, an annular recess on said shaft communicating with said opening, said iiuid metering disc disposed between said diaphragm and said recess whereby one end of said radial slot is in open communication with said central diaphragm opening and the other in open communication with said casing on one side of said diaphragm.

8. A pneumatic resistance device comprising a casing having a diaphragm secured therein and projecting thereacross, a central opening in said diaphragm, a shaft projecting through the central opening of said diaphragm for moving said diaphragm in opposite directions, a plate disposed on one side of said diaphragm for controlling the movement of the central part of said diaphragm, said plate having flanges parallel to said shaft and central opening for receiving said shaft, a valve cage secured on the end of said shaft and against the ends of the said flanges forming a space between said cage and said plate, a plurality of aligned openings formed in said cage, said plate and said diaphragm for transferring fluid within said casing between the opposite sides of said diaphragm, an annular valve disposed between said cage and said plate and around said anges formed on said plate and axially movable within said space between said cage and said plate for controlling the flow of uid in one direction through the said aligned openings, an annular recess on said shaft communicating with said opening, and a member disposed between said diaphragm and said recess and having a radially disposed metering passage, said metering passage having one end in open communication with said central opening and the other in open communication with said casing on one side of said diaphragm.

9. A diterential pressure chamber unit comprising a casing, a flexible diaphragm extending across the interior of said casing to form a chamber therein, a shaft attached to the central part of said diaphragm to move the latter and alternatively reduce or enlarge the size of said chamber, said shaft having a shoulder, means surrounding said shaft and defining a passage leading from said chamber and through said diaphragm and along said shaft, said means including a member having a second passage disposed at an angle with said shaft and partially dened by said shoulder, said second passage communicating with said rst mentioned passage, and opening through said diaphragm spaced from said shaft, and means forming a one-way valve arranged to control said opening by diterential fluid pressures acting on said diaphragm.

l0. A pneumatic resistance unit comprising a casing, a tiexible diaphragm extending across the interior of said casing to form a chamber therein, the central portion of said diaphragm being interposed between a pair of flanged plates movable with the diaphragm, the flanges of said plates being oppositely disposed to cooperate with the walls of said casing as stop means, a shaft attached to the central part of said diaphragm and to said plates to move the diaphragm and change the size of said chamber, metering means formed with a passage leading through said diaphragm and along said shaft from said chamber, at least one opening through said diaphragm spaced from said shaft, and one-way valve means arranged to control said opening by differential iiuid pressures acting on opposite sides of said diaphragm.

ll. A diterential pressure chamber unit comprising a casing, a exible diaphragm extending across the interior ot' said casing forming a chamber therein, a shaft attached to the central part of said diaphragm to move the latter for varying the size of said chamber, said shaft having a shoulder, means associated with said shaft providing a passage leading through said diaphragm along the side of said shaft, and a portion of said passage being disposed at an angle with said shaft and partially defined by said shoulder.

References Cited in the tile of this patent UNTTED STATES PATENTS 1,496,699 Wooden .lune 3, 1924 2,103,284 Whittington Dec. 29, 1937 2,190,842 Kuhn Feb. 20, 1940 2,262,823 Stearns Nov. 18, 1941 2,306,877 Gould Dec. 29, 1942 2,387,066 Harding Oct. 16, 1945 2,489,381 Lindahl Nov. 29, 1949 FOREIGN PATENTS 440,294 Great Britain Dec. 24, 1935 

